Globally flooding is becoming more and more frequent due to climate change and the increase in development on floodplain. Nearly 2 million properties are situated in flood risk areas within the UK. It is estimated that flooding has the potential to inflict damage to assets of over £200 billion. Some evidence of this can be seen in 2000, when insurance claims regarding flood damage were as high as £800 million.
Over 5% of people in England live lower then 5 meters above sea level. These locations are susceptible to frequent flooding. It has also been suggested that about 7% of the country is likely to flood at least once every 100 years from rivers. In addition, 1.5% of the country is at risk from direct flooding from the sea. Insurance companies charge huge sums to insure properties against flooding. In many instances they are not willing to insure a property at all, if located on a flood plain and at risk from regular flooding.
A number of flood defence products are currently on the market. However, only a handful of these carry the relevant kite mark relating to flood defence.
Sandbags still remain the most common method for protection and have the advantage that contours can be met, whether it is spanning a gap or assembling a defensive wall around a number of buildings. However thy have number of disadvantages, which include the following:                Time-consuming to assemble into barriers.        Prone to leakage.        Viral and bacterial infections are often present in flood water and can in turn be transferred onto used sandbags.        Large amount of material required to form a defensive wall.        Large amount of manpower required to assemble a barrier in sufficient time.        
The lengthy time needed to assemble a sandbag barrier and the manpower requirements significantly reduce the chances of a defence being erecting in time to protect against rising flood waters.
A product called Rapidam made by Flood Guards International has been displayed on Tomorrows World, where it received an award for innovation. It has been produced in a free-standing version which does not require in situ preparation, but a substantial time is needed for establishing a watertight seal and in use the resulting barrier requires a large number of sandbags.
Another product called Aqua-Barrier (Aqua Barrier International Limited) is based on a modular design and is portable and easy to deploy. It employs a linkage system that forms a watertight seal when in contact with water. However, the barrier requires in situ preparation in the form of bolts in the ground, and requires a considerable workforce to move the units into place.
GB-A-0600582 (Rowbotham) was concerned with the problem of flood protection and aimed to improve on simple banks of earth or other loose spoil which were stated not only to be laborious to construct but also to require time for settlement before they were fit for use. The proposed solution was to provide prefabricated segments which were capable of being assembled to form a bank and/or to be moved so as to enable an existing bank to be rapidly and easily re-erected on a new site. The prefabricated segments were of molded concrete and each comprised a base, a front, and two side walls, each of the side walls being formed on its outer face with a shoulder which extended from the crown to the base of the segment. One of the shoulders was arranged to face forwardly of the segment whereas the other shoulder was arranged to face rearward of the said segment. Thus by arranging a number of the segments in side-by-side relationship with their fronts in alignment, the rearward facing shoulder of each segment overlapped the forwardly facing shoulder of an adjoining segment, and a substantially watertight barrier was easily and quickly erected.
GB-A-2269618 (Tavner) disclosed a temporary anti-flood barrier comprising a water-filled wall formed by a combination of standard segments each consisting of a box section rectangular body of resilient rubber. The water filled wall was stabilized by fins built into the wall segments and by metal ribs and brackets externally on either side of the segments. A rubber under-mat formed an underseal. The wall was filled e.g. with mains water that flowed from segment to segment via water connector tubes.
GB-A-2364730 (Stuart) disclosed a portable flood barrier comprising a plurality of interlocking rubber panel segments held together at their ends by means of male/female connectors and locking arms that lock ed on to studs provided on an adjacent segment. The flood barrier was held in position by suction pads provided at the base of the segments and held in a vertical orientation by means of bracing arms.
GB-A-2397606 (Edler) disclosed a movable flood barrier comprising a watertight wall, a tank connected to the wall and an inlet in the tank for receiving water. The inlet and at least a portion of the tank were located below the top of the watertight wall. The tank could form an integral part of the wall such that the flood barrier had a substantially triangular cross-section. The base of the tank could be formed from reinforced sheeting which molded to the surface on which the tank is positioned. An air vent 4 and 5 may be provided above the level of the inlet to allow air to escape from the tank as flood water enters the tank though the inlet. Either end of the wall may be provided with means (14 and 17, FIG. 3) to connect water tightly to the end of another removable flood barrier.
GB-A-2398331 (Drury) disclosed a flood barrier unit comprising a tank formed of resilient material and having opposed front and rear walls with adjoining side walls and a base. The front wall had one or more openings at a low level to permit the inflow of water while the rear and side walls were watertight. The side walls were also shaped to co-operate with a side wall of another such unit to assist in forming a watertight seal. The base was elastic and/or flexible to conform closely to the ground under the loading provided by water in the tank. The tank could be formed as a prismatic shape with trapezoidal or triangular side walls narrower at the top than at the base. Each side wall could have a protruding section such as a generally upright corrugation or rib or a complementary recess to receive such a section.
U.S. Pat. No. 5,623,573 (Baker) disclosed a wall-like structure for flood protection, swimming pools, watering ponds for animals or other water containment purposes made of wedge-shaped plastics segments that could be coupled together to make a dam or supporting wall for containment of liquids and which found their weight by filling with water or other liquid.
US-A-2004/0190993 (Archer-Simms et al; see also WO 02/011154) disclosed a liquid barrier assembly for the prevention of flow of liquid from one area to an adjacent area The assembly comprised a plurality of hollow segments each of a plastics material e.g. polyethylene or polypropylene and each defining a substantially rigid chamber. Each segment was formed with a front concave wall against which, in use, liquid was intended to be incident. The front wall of at least one of the segments had a plurality of apertures that allowed the passage of liquid into and out of the chamber. Adjacent segments were corrected to one another in a side by side relationship by an elongate connector of bilobal or “dog-bone” section.